Various mechanisms have been used to move, release, and retrieve rigging equipment in marine environments including subsea operations. One common mechanism used includes a lifting hook (also referred to as a ROV hook or hoist hook), which includes a standard hook with a modified safety latch attached to a line. Another common mechanism includes a shackle attached to a line, the shackle having a spring loaded pin that is ejected from the shackle when a release mechanism is activated. However, these hoisting mechanisms are not without their shortcomings.
For instance, in subsea operations and depending on the load, an individual or a remotely operated vehicle (“ROV”) may be required to manipulate the hook or shackle in order to release and/or reattach the hook or shackle from/to the load. Regarding hooks, ample slack must be applied to the line in order to manipulate a hook in a manner to release the hook from a padeye of an object supporting a load attached thereto. For example, where a load is located on the seafloor, an ROV or individual must be strong enough to lift the hook and the attached rigging to create enough slack in the line to remove the hook from a padeye. In instances where the load is suspended in water, an ROV or individual must be strong enough to lift the hook, rigging, and the load attached thereto to create enough slack in the line to manipulate the hook in order to release the hook from the padeye thereby releasing the load attached thereto—usually meaning the hook has to be rotated in a manner to allow the attached load to release from the hook via gravity. Unfortunately, during the unhooking process support lines, e.g., cables, wire rope lanyards, may get kinked or damaged preventing a safety latch of the hook from closing. In addition, hook safety latches may fail due to any twisting and oscillating of loads as waves influence the vessel supporting a hook. Another negative attribute of known lifting hooks includes the possibility of unwanted foreign objects, e.g., scrap wire or rope, pushing open the safety latch and entangling the hook.
Shackles, including ROV shackles, are limited to one time use per trip subsea. And although shackles can be reassembled under water, shackles are typically more easily assembled manually at the surface with the intended rigging equipment prior to reentering the water. Also, a shackle will not release unless the attached load is completely removed from the shackle.
A load bearing device that overcomes the above mentioned shortcomings is desired.